1. Field of the Invention
The present invention relates to a machine for regeneration of pneumatic tires.
2. Description of Related Art
Machines are known which include a holding devices of the pneumatic tire to be regenerated consisting of an untranslatable, revolving drive head and a translatable, revolving idle head.
The is a adapted to axially lock the pneumatic tire (in the revolving direction of the pneumatic tire) allowing the revolution thereof only. This is an important step because the correct axial positioning of the pneumatic tire has a major influence on regeneration quality.
The idle head is translated because it is integral with a movable cylinder between an opening position and a closing position in which the pneumatic tire is made integral with both heads to allow the revolving working movement only.
Said cylinder is alternatively moved either pneumatically or by means of a motorized system with mechanical transmission, and includes a positioning stop determined by mechanically actuated blocks positioned according to the predetermined holding length. This solution has the disadvantage of needing an operator to constantly check the position of the blocks, with high risks of error and measure approximation. Furthermore, the mechanical actuation causes early component wear.
Said machines further comprise a rasp both for roughing and finishing, which usually includes a plurality (e.g. 60) of pressed harmonic steel segments on an external diameter, e.g. 310 mm, of a revolving support mounted on the tool holder spindle. Said segments form a continuous, rectilinear blade parallel to the revolving axis of the spindle: the blade substantially “scrapes” the tread while remaining parallel to the revolving axis of the pneumatic tire moved by the head itself.
Said rasp is usually actuated by motors with powers in the range between 25 and 30 kW and loadless electrical input of 23 A (Amperes), with peaks of 100 A.
In general, the known machines take 4.5 minutes to regenerate one pneumatic tire.